1. Field of the Invention
The present invention relates to a communication apparatus that communicates with an external apparatus, and a control method of the communication apparatus.
2. Description of the Related Art
Currently, there is a communication system which complies with high definition multimedia interface (HDMI) (registered trademark) standard (hereinafter referred to as an HDMI system). The HDMI system includes a source apparatus which transmits video data and a sink apparatus which displays the video data received from the source apparatus.
The sink apparatus stores extended display identification data (EDID). EDID is device information of the sink apparatus and includes information about the display capability of the sink apparatus. Japanese Patent Application Laid-Open No. 2008-160653 discusses a source apparatus that can determine a video format appropriate for the display capability of the sink apparatus by referring to the EDID acquired from the sink apparatus.
If there is an error in a cable connection between the source apparatus and the sink apparatus, a transmission error or a loss of the EDID may occur when the EDID is being transmitted from the sink apparatus to the source apparatus. For example, such transmission error or loss of the EDID may occur when chattering is generated, thereby deteriorating the EDID being transmitted. In such a case, the source apparatus may not be able to acquire the correct EDID from the sink apparatus. As a result, the source apparatus cannot recognize the video format appropriate for the display capability of the sink apparatus and thus cannot transmit the appropriate video data to the sink apparatus.
The above described issue may also occur in a communication system other than the HDMI system. For example, the problem may occur in a communication system that recognizes the video format appropriate for the display capability of the external apparatus (i.e., the sink apparatus) by the communication apparatus (i.e., the source apparatus) referring to the device information acquired from the external apparatus.